script.js

// Get references to our DOM elements
const display = document.getElementById('display');
const buttonsContainer = document.querySelector('.buttons');

// Maintain a string variable to track user input
let currentInput = "";

// Attach a single event listener to the container (Event Delegation)
buttonsContainer.addEventListener('click', (event) => {
    // Check if the clicked element is actually a button
    if (!event.target.classList.contains('btn')) return;

    // Extract the internal data value of the button
    const value = event.target.getAttribute('data-value');

    if (value === "C") {
        // Clear everything
        currentInput = "";
        display.value = "0";
    } 
    else if (value === "DEL") {
        // Remove the last character typed
        currentInput = currentInput.slice(0, -1);
        display.value = currentInput || "0";
    } 
    else if (value === "=") {
        // Evaluate the string expression safely
        try {
            if (currentInput.trim() !== "") {
                // Perform math calculation
                let result = eval(currentInput);
                
                // Keep decimal points reasonable (e.g., 0.1 + 0.2)
                if (result.toString().includes('.')) {
                    result = parseFloat(result.toFixed(4));
                }
                
                display.value = result;
                currentInput = result.toString(); // Allow continuous calculations
            }
        } catch (error) {
            display.value = "Error";
            currentInput = "";
        }
    } 
    else {
        // Prevent typing multiple consecutive operators or leading zeros brokenly
        currentInput += value;
        display.value = currentInput;
    }
});
// Listen to physical keyboard presses
document.addEventListener('keydown', (event) => {
    const key = event.key;
    
    // Map keyboard keys to calculator actions
    if (key >= '0' && key <= '9' || key === '.' || key === '+' || key === '-' || key === '*' || key === '/') {
        currentInput += key;
        display.value = currentInput;
    } else if (key === 'Enter' || key === '=') {
        event.preventDefault(); // Stop default browser behaviors
        document.querySelector('.btn.equal').click();
    } else if (key === 'Backspace') {
        currentInput = currentInput.slice(0, -1);
        display.value = currentInput || "0";
    } else if (key === 'Escape') {
        currentInput = "";
        display.value = "0";
    }
});